engleski

HYSCORE STUDY OF 14N SPLITTING FOR THE SECOND STABLE L-ALANINE PARAMAGNETIC CENTER

The stable radical formation in solid form of the simple amino acid, L-alanine, has been investigated for the long period of time (since late 1950s) by Electron Spin Resonance spectroscopy, ESR. Besides, biological relevance, there is an additional interest to reach detail description of ESR spectrum since it is used in ESR/alanine dosimetry. From the recent investigations [1] it is known that the ESR spectrum originates from ≈ 60% of • CHCH3COOH, SAR1, ≈ 40% of • CNH3CH3COOH, SAR2, and minor contribution of • CNH2CH3COOH, SAR3 centers at room temperature. For the all three centers detail protons hyperfine tensors have been estimated by ESR and ENDOR spectroscopy methods and used for assignments of these centers. However, the unpaired spin density on the nitrogen was only extrapolated and it was not experimentally measured. In the present investigation we employed 2D-HYSCORE ESR method which shows better sensitivity than the ENDOR technique to detect expected small amount of 14N coupling for the SAR2 center.

hyscore; L-alanine; SAR2

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